The present invention is directed to a child seatbelt assembly with a child resistant buckle and, in particular, to an improvement in the type of buckle commonly used in many children's safety seats, strollers, baby carriages, shopping cart seat belts, etc. A prior art buckle for use with a seatbelt assembly is made, for example, by Illinois Tool Works (ITW) and others and is well known. Referring to FIG. 9A, a prior art buckle has two latch members 10 of a male part 20 that slide into a slot 12 of a female part 30 and have barbed ends 14 that engage in female pan 30. The prior art buckle can be manipulated, by some young children, in a way that permits the buckle to be undone. As is well known, the two barbed ends 14 are pressed toward each other to allow male part 20 of the buckle to be removed from female part 30.
Others have attempted to provide a child resistant buckle for use with a seatbelt assembly. For example, see Gallbreath, U.S. Pat. No. 5,991,985 which provides a third fastening element and includes a depressable button to allow the third fastening element to be undone. This buckle is cumbersome because it requires that the user learn an additional motion in order to undo the buckle, i.e., the user must at the same time depress the side latches and the center button to undo the buckle and release the seatbelt strap.
Retainer strap seatbelt assemblies with conventional buckles are disclosed in U.S. Pat. Nos. 6,101,687 and 6,101,690, which are incorporated herein by reference in their entireties. These seatbelt assemblies are typically used in shopping carts to help restrain children in the carts and prevent injury. However, the buckles in these seatbelt assemblies are not designed to be child resistant to any certain extent.
Indeed, no readily adoptable standard for child resistant buckles is presently available. However, because of the importance of providing a child resistant buckle, it would be desirable to provide a buckle that is not easily opened by children under a certain age, for example 4 years old, but is readily opened by adults or older minors, for example, of 16 years of age or older.
An example of a child resistant buckle in a seatbelt assembly is found in U.S. patent application Ser. No. 10/081,353, the entire disclosure of which is hereby incorporated into the present application by reference. The buckle includes a number of features to increase the child resistant properties of the buckle. However, there is no readily available data that suggests one design is more appropriate for providing child resistant properties than another design.
Moreover, when the types of buckles and straps described above are used in an environment where the buckles are typically subjected to high impact and compression forces, the buckle can be damaged. A typical application for the buckles and straps are on child safety restraints, or seatbelts, used on grocery shopping carts. When carts are nested together with one another for storing large numbers of carts easily, for example, the buckles can be caught between the carts and can be subjected to high impact and compressive forces. Impact forces like these tend to cause the buckle to crack or even shatter. Compressive forces can deform the buckle beyond a point of elastic resilience, resulting in an unworkable buckle. In addition, if it is desired that the buckle exhibit certain features, such as child resistance, the forces applied to the buckle should not disrupt the desired features.
In addition, the seatbelt assembly is sometimes misused in connecting grocery carts together, for example, to tow a number of carts together. These occasions of misuse can produce high tensile strain on the buckle, causing the buckle to fail and resulting in damage to buckle components.